Multi-track mixing has been used within recording studios for many years. Originally, two or more tape recorders each stored one musical track of sounds (e.g., voice, guitar, drums) that were combined together to form a musical recording (e.g., a song, orchestral piece, or sound track) when the plurality of tracks were played back simultaneously. Typically, these tracks are played into a mixing device where the volume (and other characteristics) of each track is controlled (e.g., faded in and out) to produce the audio title (hereinafter ‘song’) as two stereo audio tracks that are recorded onto another tape recorder in preparation for mass productions of vinyl records, CDs and other formats. The tape recorders and mixing devices were originally analog (i.e., handling analog audio signals) and later developed into digital devices that handle audio in a digital format (e.g., pulse-width modulation (PWM), MP3 and other digital audio format files). The resulting song is a stereo audio format that is generated from the original recorded tracks. Songs purchased by consumers are typically produced in this way, such that the consumer purchases only the mixed stereo audio. For example, CDs and MP3 files are composed of only two premixed stereo audio channels that are played simultaneously.
Although prior art multi-track recorders allows individual tracks to be mixed together, these tracks were used much like the way loops and samples are used within modern audio workstations. There is no automatic synchronization of the tracks; each track must be started at the right time by the operator. Starting and stopping of each track at the correct time is very difficult and prone to error, and is not something that can be done in real-time during a performance.
To play music at a venue, a disk-jockey (DJ) operates a DJ console to select and play songs. The songs may be played from a media (e.g., CD or flash drive) or selected from a digital library, stored on a computer for example. The DJ often plays and mixes two songs together, for example when transitioning from a first song to a second song such that the performance is continuous. The DJ may also selectively mix high, medium, and low frequency components of two songs together, to form a stereo audio output (called a “mix”) that is heard by the audience. The mix may also be recorded and sold as a “performance” by the DJ.
FIG. 1 is a schematic showing a prior art DJ console 102 that is used to create a mix 104 from five songs 106(1)-(5). Console 102 has two decks 110(1) and 110(2), each with a mixing control set 112(1) and 112(2), respectively. Decks 110 are for example CD players and/or shuttle/nudge controls for other digitally stored audio sources. Using the mixing controls 112, the DJ selects an amount of high, mid, and low frequency range signal from the audio of each deck 110 for mixing together. The DJ uses the shuttle/nudge controls for each deck to ensure that the beats within each audio source are synchronized before mixing.
In the example of FIG. 1, during a performance to create mix 104, the DJ first mounts song 106(1) on deck 110(1), adjusting mixing control set 112(2) to output no sound from deck 110(2), and adjusting mining control set 112(1) to output audio from deck 110(1). The DJ mounts song 106(2) on deck 110(2), synchronizes the beat from deck 110(2) with the beat from deck 110(1), and at the appropriate time mixes audio from song 106(2) with the audio of song 106(1) using audio mixing control set 112(2) (and optionally audio mixing control set 112(1)). Once song 106(1) has been faded out, the DJ replaces song 106(1) with song 106(3) on deck 110(1). The DJ then synchronizes the beat of song 106(3) with that of song 106(2), and at the appropriate time, uses mixing control set 112(1) to mix song 106(3) with song 106(2). Once song 106(2) has been mixed out, the DJ replaces song 106(2) with song 106(4) on deck 110(2). The DJ then synchronizes the beat of song 106(4) with that of song 106(3), and at the appropriate time, uses mixing control set 112(2) to mix song 106(4) with song 106(3). This process repeats to mix in and switch to each song 106.
The songs that are available to DJs are stereo (i.e., two channel) formed by mixing individual sounds from multiple tracks together. Although the DJ attempts to select certain sounds from each song for mixing, this is limited to the frequency/bandwidth based selection provided by audio mixing control sets 112.